Objective: An investigation of the outbreak was initiated as a result of the number of cases of gastroenteritis reporting to a general hospital in Mina during the pilgrimage to Makkah (HAJJ). This study was conducted to identify the source of the outbreak, assess its extent, and make recommendations to prevent similar outbreaks in the future. Methodology: A case was defined as any individual who developed diarrhea with or without abdominal pain after eating at the camp in Mina on 3 rd January 2006. A retrospective cohort study was conducted to identify food items and circumstances responsible for this outbreak. Laboratory tests included stool cultures of all diarrhea patients, and rectal swabs from all food handlers were cultured for enteric pathogens. Results: A total of 50 Saudi Male Soldiers were interviewed. Out of these, 16 (39%) had developed gastroenteritis, most commonly manifested by diarrhea (100%), and abdominal colic (87.5%). The mean incubation period was 12.6 ± 4.9 hours and the epidemic curve suggested a common point source outbreak. Out of three served meals, lunch was found to have a statistically significant association with illness (p=0.0230). Out of five food items served, rice was the only food item found to have a statistically significant association with illness (p=0.0230). No food remnants were found for sampling. All results of stool cultures of all diarrhea patients, and rectal swabs from all food handlers were inconclusive. Conclusions: This outbreak was most likely caused by eating contaminated rice served at lunch on 3 rd January. The most likely organisms were Bacillus cereus, and/or Clostridium perfringens. Consuming food that was kept at an unsafe temperature wihout being reheated was the most probable important factor leading to this outbreak.